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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

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subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

26119 results found.

  1. GRB 250806A: SVOM/VT refined analysis
  2. GRB 250806A: Swift-XRT counterpart detection
  3. GRB 250805A: SVOM/VT optical counterpart
  4. GRB 250805A: ESO/VLT observations
  5. GRB 250805A: Swift-XRT refined Analysis
  6. GRB 250804B: Swift-XRT observations
  7. GRB 250805A: Enhanced Swift-XRT position
  8. GRB 250805A: TRT optical upper limits
  9. GRB 250805A: Swift-XRT observations
  10. GRB 250805A: Swift detection of a burst
  11. Swift GRB250805.26: Global MASTER-Net observations report
  12. GRB 250804B: Tiled Swift observations
  13. EP250802a: GROWTH-India Telescope optical upper limit
  14. LIGO/Virgo/KAGRA S250727dc: GRANDMA/OPD observations of AT2025smm
  15. LIGO/Virgo/KAGRA S250727dc: DECam DESGW Epoch 1 Candidates
  16. GRB 250727A: Swift-XRT afterglow confirmation and refined analysis
  17. LIGO/Virgo/KAGRA S250727dc: Swift-UVOT follow up of AT 2025smm
  18. LIGO/Virgo/KAGRA S250726ak: Upper limits from Swift/BAT-GUANO
  19. LIGO/Virgo/KAGRA S250725l: Upper limits from Swift/BAT-GUANO
  20. LIGO/Virgo/KAGRA S250727dc: Upper limits from Swift/BAT-GUANO
  21. LIGO/Virgo/KAGRA S250727dc: Swift-XRT observations, 8 X-ray sources
  22. GRB 250725A: AstroSat CZTI detection
  23. GRB 250727A: EP-FXT follow-up observation
  24. GRB 250725A: PRIME near-infrared observations
  25. LIGO/Virgo/KAGRA S250727dc: DECam GW-MMADS upper limits of AT 2025smm
  26. LIGO/Virgo/KAGRA S250727dc: PRIME J-band upper limits of AT 2025smm
  27. GRB 250728A: Swift-XRT observations
  28. GRB 250728A: COLIBRÍ optical upper limit
  29. GRB 250728A: Fermi GBM Observation
  30. LIGO/Virgo/KAGRA S250727dc: Swift-UVOT detection of a new source, AT 2025smm
  31. GRB 250728A: Swift ToO observations
  32. GRB 250728A: Swift/BAT-GUANO arcminute localization of a short burst
  33. GRB 250727A: EP-FXT counterpart detection
  34. GRB250727A: SVOM/VT optical upper limit
  35. GRB 250727A: Swift-XRT observations
  36. Swift detection of the Soft Gamma Repeater PSR J1647-4552
  37. GRB 250725A: Swift-XRT refined Analysis
  38. GRB 250725A: Fermi GBM Observation
  39. GRB 250725A: Swift-BAT refined analysis
  40. Konus-Wind detection of GRB 250725A
  41. GRB 250725A: SVOM/GRM observation
  42. GRB 250725A: Global MASTER-Net: First Optical Synchronous Observatios of Short GRB.
  43. GRB 250725A: Swift/UVOT Upper Limits
  44. GRB 250725A: Fermi-LAT detection
  45. GRB 250725A: VLT/FORS2 spectroscopic redshift z = 5.26
  46. GRB 250725A: BOOTES-7 early optical detection
  47. GRB 250725A: SVOM/VT optical candidate
  48. GRB 250725A: MASTER-OAFA optical detection of very fast afterglow
  49. GRB 250725A: Enhanced Swift-XRT position
  50. GRB 250725A: Swift detection of a burst
  51. Swift GRB 250725A: Global MASTER-Net OT detection
  52. Swift GRB 250725A: Global MASTER-Net observations report
  53. SVOM J195836+32283/sb25072103: Swift XRT/UVOT upper limits
  54. Swift-BAT trigger 1334535 is not a GRB
  55. GRB 250721A: Swift-XRT observations
  56. GRB 250717B: SVOM/GRM observation
  57. GRB 250721A: Tiled Swift observations
  58. GRB 250717B: COLIBRÍ optical upper limit
  59. LIGO/Virgo/KAGRA S250711q: Upper limits from Swift/BAT-GUANO
  60. GRB 250717B: Swift-XRT observations
  61. Swift Trigger 1334535 / GRB 250718A: COLIBRÍ optical upper limits
  62. Swift Trigger 1334535: a possible GRB 250718A
  63. Swift GRB250718.01: Global MASTER-Net observations report
  64. GRB 250717B: Swift ToO observations
  65. GRB 270713A: Kitab and AbAO Optical Observations
  66. GRB 250717B: Fermi GBM Observation
  67. GRB 250717B: Swift/BAT-GUANO arcminute localization of a burst
  68. GRB 250716A: Swift-XRT afterglow detection
  69. GRB 250716A: Lesedi Detection of Fading Optical Transient GOTO25eyp
  70. GRB 250716A: Swift ToO observations
  71. GRB 250713A: SVOM/VT optical upper limit
  72. GRB 250713A: SVOM/C-GFT upper limit
  73. GRB 250713A: Swift-XRT observations
  74. GRB 250706A: Swift-BAT refined analysis
  75. GRB 250702F: Swift-BAT refined analysis
  76. GRB 250628A: Swift-BAT refined analysis
  77. GRB 250704B / EP250704a: 1.3 GHz MeerKAT Detection
  78. LIGO/Virgo/KAGRA S250629bs: Upper limits from Swift/BAT-GUANO
  79. LIGO/Virgo/KAGRA S250629ae: Upper limits from Swift/BAT-GUANO
  80. GRB 250702B,D,E/EP250702A: MeerKAT radio observations at 1.28GHz
  81. GRB250702 B,D,E / EP250702a: MOSFIRE imaging of the afterglow
  82. GRB 250704B / EP250704a: VLA radio detection
  83. GRB 250706B: SVOM observations interpreted as the afterglow of GRB 250706C
  84. GRB 250704B / EP250704a: Mondy and AbAO optical observations
  85. GRB 250706B/C: VLT/X-shooter redshift z = 0.942
  86. GRB 250706B/C: Fermi-LAT detection
  87. GRB 250706B: Swift/UVOT Detection
  88. EP250702a/ GRB 250702B: NuSTAR X-ray Observations
  89. GRB 250704A: Swift/BAT-GUANO localization skymap of a burst
  90. GRB 250702F: GRANDMA observations
  91. GRB 250706A: Swift-XRT refined Analysis
  92. GRB 250706B: refined SVOM/MXT data analysis
  93. GRB 250706A: Swift/UVOT Upper Limits
  94. GRB 250706B: REM optical observations
  95. GRB 250706A: REM optical/NIR observations
  96. Swift GRB 250706A: Global MASTER-Net observations report
  97. GRB 250706A: JinShan optical upper limits
  98. GRB 250706A: SAO RAS optical observations
  99. EP250704A: NOWT Detection
  100. GRB 250706A: SVOM/C-GFT upper limit in eary phase

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